diy solar

diy solar

Heltec (JK) 200A Smart BMS with 2A Active Balance

GXMnow said:
That's looking good. Very clean.

I don't know why JK does not put mounting tabs on the BMS housing. I ended up getting longer screws to replace the ones holding the case together. And then bolted 4 of them through a rack panel that is bolted into my battery cabinet. IT was a major pain to get the holes to line up, and then I also realized how NOT flat the back of the BMS housing is. So I used a few varying layers of thermal transfer tape. The stuff that is used to attach small heat sinks onto IC chips. Just one layer on the highest part, and then stacked up more layers to fill the gap as the case curved away from the plate. I was worried about heat build up, so I wanted the large aluminum plate to act as more heat sink, but it turns out it never gets more than just warm at the 80 amps my system maxes out at.

The cheap basic dumb Daly BMS units I used on my second battery bank are nearly flat, and have cast in metal mounting ears for screws. It made it so much easier to hold it where I wanted it, and just mark through the holes and drill them. Maybe JK could learn something there.
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My Jk BMS has 4 holes with m3 threads which I did use for mounting. The holes are 4,5mm deep so one must pay attention to not rip the thread out the alumin(i)um
 
Diesel Pro said:
I found the same android 12 issue but app version 3.7.5 does work.

As for fluctuating current reading it also does this when charging, maybe a bit less. I really like this BMS. It would be nice to have this aspect fixed.
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Has there been a fix for this yet ?? I have 3 older units, they are steady amps... I just fired up 3 new ones,,All same settings as old ones.. and the amps jump all over the place... What's going on...
 
curiouscarbon said:
intesting, thank you for the in depth description of how AC inverter draws Varying DC amps

well said!

as you mention, one way to get around this issue at a Firmware Level is to sample the Battery Current at e.g. 120hz and only report averages that cover an integer number of AC cycles (1 cycle = 1/60 second, 2 cycle = 2/60 second). It Must Be Integer Multiple Number Of Cycles.

zero crossing average would drastically reduce the fluctuation

i have had to do this before writing low level microcontroller firmware. sampling like this would completely negate that part of the fluctuation.

if BMS reads current and reports over time periods that are not 1/30th of a second precisely or 1/15th of a second precisely, this fluctuation will never go away is my theory. good luck!

oh... if running the inverter at 50hz change all the values. or to whatever frequency for locale.

excited for the 4S BMS after new years celebration :)
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If this is the case, then why do BMS's 1-3 work fine ( older ones i got nearly 2 yrs ago ) and BMS's 4-6 New ones i got just a few months ago ,jump all over the place ? All 6 of my strings are parallelled.... 14S6P
 
Dacflyer said:
If this is the case, then why do BMS's 1-3 work fine ( older ones i got nearly 2 yrs ago ) and BMS's 4-6 New ones i got just a few months ago ,jump all over the place ? All 6 of my strings are parallelled.... 14S6P
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This is only a guess. Maybe the sample period of the older units firmware happened to luck out with the AC line frequency where you are, so it kept sampling at about the same point of the waveform. Maybe the old firmware did a running average. But in reality, a running average, though nice to look at as it smooths out variations, can actually cause errors as it could miss short term changes in current.

How close do the state of charge readings track? I know my 2 banks of newer cells are running a little more energy than my two older strings, but overall, the state of charge % stays very close between them. If the old ones are doing a running average, it might creep off and show a different amount of total amp hours used. If it just samples in one place on every cycle, it would not know if that is the peak current, or it could be near the zero crossing. So a smooth reading could be a little high to very low. But if it randomly samples all over the waveform, it should average out to the correct current over time. It looks worse, but could actually be a better total reading over time.
 
Maybe I'm missing something.. I am not dealing with any AC.. The batteries and BMS's aren't tied to the AC line at all..
I'm Referring to the JK BMS's I have...I have 6 of them now..
the 1st 3 are giving better % and capacity since i been bumping up the AH cap., But the Batteries are only about 75AH,, but to get a realistic reading, i had to bump up the Ah cap to 200AH... You remember i talked to you about this long ago.. Other than that, i have had no issues..
Anyway, the new ones are set up exactly the same and work fine, except for the Amp reading is just jumping all over.. The Inverter shouldn't have anything to do with the issue..and with so much DC, there shouldn't be any AC feedback..
Maybe The Kind lady that's representing the BMS on here might have some info.. But i Believe it's a firmware issue..
 
Dacflyer said:
Maybe I'm missing something.. I am not dealing with any AC.. The batteries and BMS's aren't tied to the AC line at all..
I'm Referring to the JK BMS's I have...I have 6 of them now..
the 1st 3 are giving better % and capacity since i been bumping up the AH cap., But the Batteries are only about 75AH,, but to get a realistic reading, i had to bump up the Ah cap to 200AH... You remember i talked to you about this long ago.. Other than that, i have had no issues..
Anyway, the new ones are set up exactly the same and work fine, except for the Amp reading is just jumping all over.. The Inverter shouldn't have anything to do with the issue..and with so much DC, there shouldn't be any AC feedback..
Maybe The Kind lady that's representing the BMS on here might have some info.. But i Believe it's a firmware issue..
Click to expand...
Just to clarify, you do not have an inverter connected to your batteries?
 
I do have an inverter connected ( AIMES Brand ) the issue is not with the older units,, just the newer ones.. they are all on the same bus bar
so why is only the new ones effected ? I used my scope today,,the DC rail is clean as can be.. I do not detect any noise on the line..

On a Plus note...these new units have a much better BT range. I can check things from the living room,, I wonder if there's anythng i can do to the older units to improve the range.. If i'm more than 10ft away i loose signal..
The new ones i can be over 30ft away..

So 1 things improved and another went downhill..
 
Nami said:
In fact, we have been updating our products according to the needs of our customers. However, with the update, there will be some problems. The original customers will feel bad, but it is these needs that drive us to pursue perfection and provide customers with a better experience. We are customizing the BMS communicating with victron, GPS functions that can support other countries, and jk-b2a4s20p. These are all things that need to be completed in 2022
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Hi,, could you please have a look at my recent post and tell me if there is a solution..thanks you..
 
Scph9002 said:
where and how can i flash new firmwares?
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Can't. I've asked for the source code, and there is apparently some work going on to release it.
There is a programming header on the board, and it's an STM32 (or clone), so flashing it is a piece of cake. One could even create a bootloader that can flash new firmware over a uart (the existing RS485 port or CAN one) or something. Hopefully the source gets released at some point...
 
upnorthandpersonal said:
Can't. I've asked for the source code, and there is apparently some work going on to release it.
There is a programming header on the board, and it's an STM32 (or clone), so flashing it is a piece of cake. One could even create a bootloader that can flash new firmware over a uart (the existing RS485 port or CAN one) or something. Hopefully the source gets released at some point...
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or atleast a proper bug free firmware/software that is flashable over android or pc software
 
Did anyboty try to convert JK BMS errors/warnings to Pylon CANBUS protocol? I have created board to read data from JK BMS by RS485 protocol and send this data to CAN bus with "PYLON low voltage protocol". It should works but i need to understand how to convert JKBMS errors to pylon erros. It is not clear for me.
 
I've been just using JBD BMS's on my 4 previous builds, and I'm getting ready to build another 8S 24V battery, and thought I should at least consider the JK instead.

After skimming through 26 pages of posts in this thread and watching a couple of Andy's ( @Off-Grid-Garage ) videos, I've got several questions:
  1. If I get one of the JK units that explicitly supports 8S, will I still need a 40V or higher power source? (I think not, but that would be a deal breaker for me)
  2. Has the rapidly fluctuating current (and voltage?) measurements been fixed in the currently available BMS's?
  3. Has the Android version of the app been fixed for Android 12? I'm currently on Android 11, but I'm pretty sure my relatively new phone will be doing an OTA upgrade soon.
  4. Is there or is there not some strange thing I need to do to "boot" the JK BMS, or does it just run when it has power like the JBD?
  5. I was looking mostly at the Hankzor Aliexpress store (are there others for the JK BMS?). If I want 8S, >200A would the B2A8S20P be the right one to get?
I really appreciate anyone who can help me get my JBD head wrapped around the JK BMS. Thanks!
 
1) yes
2) no, but know that it doesn't really matter
3) don't know
4) new version has a screen with power button accessory. Otherwise you need to boot it with e.g. a 9V battery
5) I believe Hankzor is doing development on the BMS, so I would buy from them right now. Previous versions available from different vendors can even have completely different firmware and don't support the power button etc.

one more) don't buy from them. They're older versions.
 
upnorthandpersonal said:
4) new version has a screen with power button accessory. Otherwise you need to boot it with e.g. a 9V battery
5) I believe Hankzor is doing development on the BMS, so I would buy from them right now. Previous versions available from different vendors can even have completely different firmware and don't support the power button etc.
Click to expand...
Thanks @upnorthandpersonal. Can you explain what the "power button accessory" is, physically? The BMS itself has a momentary contact push button on it somewhere?

Edit to add: Is there a way to tell if the model I'm buying has the power button accessory?
 
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